1. Field of the Invention
The present invention relates to a winding shaft for winding therearound a recording medium such as journal paper or the like, and a printer using such a winding shaft.
2. Description of the Related Art
Conventionally, for the purpose of sales and inventory management in a store or the like, there has been a requirement to keep journal paper on which selling prices, names of articles and the like are printed. Therefore, a printer that is structured such that it winds the printed journal paper around a winding shaft has been proposed. An example printer of this type is shown in FIG. 26.
Referring to FIG. 26, this printer 101 is a dot impact printer, which is incorporated into a cash register or the like. The printer 101 includes printer main body 103, a clamshell mobile part 104, and a winding mechanism 105. A ribbon cassette 102 can be removably mounted on the printer main body 103. The clamshell mobile part 104 is movably supported at a position on the printer main body 103 located near the rear portion of the upper portion of the printer main body 103. The winding mechanism 105 is disposed in the rear of the printer main body 103. Recording paper 106, such as journal paper printed by a print head (not shown) or the like, is fed out upwardly of the clamshell mobile part 104 by a paper feed mechanism 107, is then passed through a plane portion 108a of a writing base 108 for print correction, and is finally wound around a winding shaft 109 of the winding mechanism 105.
The winding shaft 109 is rotatably supported in a cantilevered manner while a disk-shaped winding flange 111 is fixed to a portion of the winding shaft 109 on the support plate 110 side thereof. Also, a driving gear 112 is fixed to the leading end portion of the winding shaft 109 on the support plate 110 side thereof. The winding shaft 109 can be driven or rotated via meshing engagement between a gear train 114 and the gear 112 fixed to the winding shaft 109. The gear train 114 can be driven or rotated by a winding belt 113 linked to and movable with the paper feed mechanism of the printer main body 103.
In the printer 101 of this type, it is necessary to remove the recording paper 106 from the winding shaft 109 after it is wound therearound. However, because the recording paper 106 is wound tightly, it is not easy to remove the recording paper 106. That is, the recording paper 106 sticks to the winding shaft 109, resulting in the center of the recording paper 106 becoming shaped like bamboo shoots.
In order to solve the above problem, conventionally there has been proposed a paper-winding device structured such that the outside diameter of a winding shaft can be changed. (For an example, see Japanese Utility Model Publication No. 55-66156 of Showa). However, in this conventional device, it is necessary to apply an external force to the winding shaft in the axial direction thereof in order to change the outside diameter of the winding shaft. Since this external force is different from a force required to remove the recording paper, the operation of this conventional device is troublesome.